CODEPOSITION ON HOT CVD SURFACES - PARTICLE DYNAMICS AND DEPOSIT ROUGHNESS INTERACTIONS

To capture in a tractable manner essential coupling effects in CVD sys tems when particles generated in thermal boundary layers also deposit, a film theory was developed that predicts simultaneous vapor and part icle deposition rates at a hot deposition surface. The codeposition ra te prediction method also calculates for the first time the correspond ing solid deposit roughness using recently published results of partic le-level simulations. For the numerical illustrations, the growth of T iO2(s) films by the codeposition of titanium tetra-isopropoxide vapor and film-nucleated/grown TiO2 particles (generated in the thermal boun dary layer) was considered. Experimental rate data for this system are available. The continuum and particle-level simulation methods provid e: the interplay of vapor precursor kinetics, particle nucleation, gro wth, coagulation and division in determining the complex ''structure'' of such multiphase chemically reacting boundary layers; wall depositi on rates of both surviving vapors and film-nucleated particles; and th e ''self-consistent'' microstructure (surface roughness) of the result ing solid deposit timely and tractable generalizations are discussed i n the light of recent results for the transport properties and stabili ty of ''fractal-like'' aggregated particles.